A Spare Tire That Fits Under the Load Floor

[Frenzal]

Got links for the rims and tires you used?
Have you been able to test how the stock lugs press against the rims?

I apologize if you mentioned already brother

Please read my posts in this thread: https://www.integraforums.com/forum/threads/spare-tire-kit.51075/

All info is there. As for the tire, I bought it locally, but you can find it at Tire Rack (it was in stock last summer when I looked).

 

[kjechel]

Got links for the rims and tires you used?
Have you been able to test how the stock lugs press against the rims?

I apologize if you mentioned already brother

Sorry, I thought you were asking me, but in any case, someone may find the following useful:

Wheel: www.ecstuning.com/b-genuine-bmw-parts/black-steel-emergency-wheel/36116758778
Tire: Continental sContact T115/95R17

My hub centric rings should arrive late today, so a test drive is planned for tomorrow. I've flip-flopped on my preference of the lug nuts - I think I prefer the M14 x 1.5 Flange Nuts. Reason being that the metal to metal contact between the OEM lug nuts and lug nut seats of the wheel score up the lug nuts a little. If you go this route, use some anti-seize on the mating surfaces.

You may be able to find M14 x 1.5 Flange Nuts in your local hardware store (I did, and less expensive than these from Amazon) . They are Grade 10 and very hard, so they don't get chewed up at all on the mating surface. Make sure to get the non-serrated type (flat surface on back, not grooved).

One small additional advantage of the Flange Nuts is that if you are concerned about them staying tight and not loosening, you could add Jam Nuts on top of the Flange Nuts. There's just enough stud sticking out to allow that

 

[Nickp15]

Lmao keep it coming baby. Sunk cost fallacy something something That RL tire option starting too look a lot sexier

 

[Nickp15]

But seriously thank you @kjechel and @Frenzal . You guys are fucking awesome for taking so much time and going into so much detail to help folk for something Acura should have done. Maybe they ought to send you a check

 

[thui001]

As delivered, the holes in the wheel are just barely big enough to allow 14mm studs to fit through. Any distortion risks locking the wheel on the studs - a big problem. Opening up the holes is easy with a step drill.

How much opening is needed using a Step drill? Your write up is amazing. Thank you.

 

[Compromise]

How much opening is needed using a Step drill? Your write up is amazing. Thank you.

He noted 9/16" in previous posts.

 

[thui001]

He noted 9/16" in previous posts.

Thank you so much. Sorry I must over read it.

 

[kjechel]

He noted 9/16" in previous posts.

Yes, 9/16" (0.562" or 14.3 mm). 19/32" (0.594") would be OK too, but the step drill's next size up (for the one @Nickp15 bought) is 5/8" (0.625") which I think is a little too big.

A few more tips:
1. Put some masking tape (or marker pen) on the next step above 9/16" on the step drill so you don't accidentally go past to the next size up. If you have a variable speed drill, start by using a slow speed, as any "grabbing" of the bit in the hole will be reduced. With a step drill you'll experience much smoother cutting with less grabbing (compared to a common spiral fluted drill bit) because there is only a single cutting edge on the step drill. If you've never used a step drill before, it will become your favorite tool for making holes in sheet metal.

2. On your last round of drilling (after your last round of torqueing) use the chamfered (lead-in) portion of the next step to lightly chamfer and deburr the top edge of each drilled hole.

3. If you are using Flange Nuts as your lug nuts, a washer between the back of each nut and lug nut seat on the wheel will make the seat "flattening" process even easier. A common (USS) 1/2" flat washer will work fine, but not an SAE 1/2" (the ID is too small to fit over the 14mm stud). Or of course a metric M14 flat washer will work fine as well. But don't include the washers when you are using the wheel on the road as your spare tire - It might make the nuts come loose more easily.

4. Re: Lug Nut Torque - At only 50 ft-lbs of lug nut torque, the calculated clamping load PER STUD is ~5400 lbs for unlubricated and ~6800 lbs (+25%) for lubricated studs & nuts. So if you are applying anti-seize as I recommended, you'll have ~6800 x 5 = ~34,000 lbs of force holding the wheel on at only 50 ft-lbs of lug nut torque. I don't see any reason to go above 60 ft-lbs, especially since I was experiencing some deformation of the wheel (outside of the lug seat area) at torques above 70 ft-lbs. As an extra measure of safety, you can add Jam Nuts on top of the Flange Nuts for additional peace of mind.

My hub centric rings arrived today, so I will be testing the wheel & tire tomorrow and will report back with my results.

 

[Nickp15]

Yes, 9/16" (0.562" or 14.3 mm). 19/32" (0.594") would be OK too, but the step drill's next size up (for the one @Nickp15 bought) is 5/8" (0.625") which I think is a little too big.

A few more tips:
1. Put some masking tape (or marker pen) on the next step above 9/16" on the step drill so you don't accidentally go past to the next size up. If you have a variable speed drill, start by using a slow speed, as any "grabbing" of the bit in the hole will be reduced. With a step drill you'll experience much smoother cutting with less grabbing (compared to a common spiral fluted drill bit) because there is only a single cutting edge on the step drill. If you've never used a step drill before, it will become your favorite tool for making holes in sheet metal.

2. On your last round of drilling (after your last round of torqueing) use the chamfered (lead-in) portion of the next step to lightly chamfer and deburr the top edge of each drilled hole.

3. If you are using Flange Nuts as your lug nuts, a washer between the back of each nut and lug nut seat on the wheel will make the seat "flattening" process even easier. A common (USS) 1/2" flat washer will work fine, but not an SAE 1/2" (the ID is too small to fit over the 14mm stud). Or of course a metric M14 flat washer will work fine as well. But don't include the washers when you are using the wheel on the road as your spare tire - It might make the nuts come loose more easily.

4. Re: Lug Nut Torque - At only 50 ft-lbs of lug nut torque, the calculated clamping load PER STUD is ~5400 lbs for unlubricated and ~6800 lbs (+25%) for lubricated studs & nuts. So if you are applying anti-seize as I recommended, you'll have ~6800 x 5 = ~34,000 lbs of force holding the wheel on at only 50 ft-lbs of lug nut torque. I don't see any reason to go above 60 ft-lbs, especially since I was experiencing some deformation of the wheel (outside of the lug seat area) at torques above 70 ft-lbs. As an extra measure of safety, you can add Jam Nuts on top of the Flange Nuts for additional peace of mind.

My hub centric rings arrived today, so I will be testing the wheel & tire tomorrow and will report back with my results.

Anxious to hear your results! BTW, have you checked to see what Acura recommends as far torquing for the spare?

 

[kjechel]

My hub centric rings arrived today, so I will be testing the wheel & tire tomorrow and will report back with my results.

These hub centric rings are very nicely machined and fit great. It friction fit into the center of the spare tire's wheel, so it can stay there and not get lost when stored away. It has just enough clearance to fit easily over the hub of the car but still accurately locate the wheel. With the wheel still off the ground I checked for runout. I couldn't see any - the wheel and tire run very true.

I drove 12 miles on the twisty canyon roads around my home at 40 - 60 MPH with the spare tire on the left rear. I torqued the nuts to only 50 ft-lbs (and no jam nuts) with the idea that if they would loosen, it would more likely happen at this low torque. (For an on-the-road emergency installation of the spare I'd recommend 60 - 70 ft-lbs, but not more as it clearly isn't needed, and install the jam nuts if you have them, for extra security).

I'm happy to report that the nuts didn't loosen at all (I stopped 3 times to check) and the handling was fine, nothing funky. The TPMS light came on at mile 8 (which I expected) telling me to "see my dealer" - really?

So this wheel & tire combination appears to work just as intended. If you follow this same path, I recommend that you do a trial run as well so you know you can depend on it in an emergency. Please share your results with the rest of us.

 

[Nickp15]

These hub centric rings are very nicely machined and fit great. It friction fit into the center of the spare tire's wheel, so it can stay there and not get lost when stored away. It has just enough clearance to fit easily over the hub of the car but still accurately locate the wheel. With the wheel still off the ground I checked for runout. I couldn't see any - the wheel and tire run very true.

I drove 12 miles on the twisty canyon roads around my home at 40 - 60 MPH with the spare tire on the left rear. I torqued the nuts to only 50 ft-lbs (and no jam nuts) with the idea that if they would loosen, it would more likely happen at this low torque. (For an on-the-road emergency installation of the spare I'd recommend 60 - 70 ft-lbs, but not more as it clearly isn't needed, and install the jam nuts if you have them, for extra security).

I'm happy to report that the nuts didn't loosen at all (I stopped 3 times to check) and the handling was fine, nothing funky. The TPMS light came on at mile 8 (which I expected) telling me to "see my dealer" - really?

So this wheel & tire combination appears to work just as intended. If you follow this same path, I recommend that you do a trial run as well so you know you can depend on it in an emergency. Please share your results with the rest of us.

Thank you so much for the detail. Couple questions if possible,
1)in which direction dill you drill when widening the wheel holes? I'm not sure if it matters?
2) Which lug nuts did your end up going with? OEM?
3)Did you end up keeping the wood block to keep the wheel even or swapped to something else?
4) for silicone sealant would you recommend the loctite one? It's advertised as adhering to aluminum:
Loctite 908570 2.7 oz Tub Clear Silicone Waterproof Sealant, Single Tube https://a.co/d/bubWx7x

Thank you so much!

 

[kjechel]

Thank you so much for the detail. Couple questions if possible,
1)in which direction dill you drill when widening the wheel holes? I'm not sure if it matters?
2) Which lug nuts did your end up going with? OEM?
3)Did you end up keeping the wood block to keep the wheel even or swapped to something else?
4) for silicone sealant would you recommend the loctite one? It's advertised as adhering to aluminum.

Thank you so much!

You're welcome!
1. I drilled first from the outward facing side, but also from the other side as well to ensure that I had a clean hole all the way through (the step in the drill isn't very deep). In the end it really doesn't matter.

2. In Post #47 I said: " I've flip-flopped on my preference of the lug nuts - I think I prefer the M14 x 1.5 Flange Nuts. Reason being that the metal to metal contact between the OEM lug nuts and lug nut seats of the wheel score up the lug nuts a little. If you go this route, use some anti-seize on the mating surfaces. "

3. I still have that same piece of 2x2 (measures 1.5" x 1.5") x ~8" long. It seems to work fine and you can't see it when the tire is covering it. A scrap of 2x4 (1.5" x 3.5") should work as well - anything that spaces the front of the tire up ~1.5" is fine, so its plane is parallel with the load floor.

4. I don't think I ever mentioned silicone sealant, did I? If yes, for what? Do you mean anti-seize? This is available from Amazon: https://www.amazon.com/dp/B01LWVT2DK, but your local auto parts store has it as well, I'm sure. It's like a silver colored grease that keeps metal from galling and sticking together under high contact force. Use sparingly - a little goes a long way. Apply a tiny bit on all of your wheel studs to prevent corrosion and stuck lug nuts in the future.

 

[kjechel]

4) for silicone sealant would you recommend the loctite one? It's advertised as adhering to aluminum:
Loctite 908570 2.7 oz Tub Clear Silicone Waterproof Sealant, Single Tube https://a.co/d/bubWx7x

OK, now I remember about the silicone sealant to seal the holes in the floor of the spare tire well - sorry. Yes, I think the one you referenced should work fine. I used some I had left over from a roofing job - the exact formulation is not that critical. If you are ultra worried about water intrusion you could also spray some undercoating or apply a layer of roofing tar, but not necessary IMO.

 

[Nickp15]

OK, now I remember about the silicone sealant to seal the holes in the floor of the spare tire well - sorry. Yes, I think the one you referenced should work fine. I used some I had left over from a roofing job - the exact formulation is not that critical. If you are ultra worried about water intrusion you could also spray some undercoating or apply a layer of roofing tar, but not necessary IMO.

Yes I was referring to the silicsmt sealant for the mounting screw holes. For the sake of everyone following along I ended up going with this other loctite silicone sealant which is specifically marketed for vehicles. Probably same crap but oh well here is the link:LOCTITE RTV Clear Silicone Adhesive Sealant for Automotive: Waterproof, Flexible, Protects Wiring, For Glass, Metal, Plastics, and more | Clear, 80 ml Tube (PN: 491981) https://a.co/d/9TVDffP


Thank you so much for the detailed help man. Drilling into my baby is got me sweating bullets. I'll take my time and follow instructions. Will post result.

I'll probably go the wood route too. A foam piece might break off over time. I got some felt material laying around I could wrap around the wood for a clean look.

By the way how did you fix the wood block to the car?

 

[kjechel]

By the way how did you fix the wood block to the car?

I'm ashamed to admit right now it's just being squeezed down by the tire which is held down by the Mounting Screw. I'll probably just use some double-stick foam tape.